Liquid crystal display device and electronic apparatus

ABSTRACT

There is provided a liquid crystal display device that includes a first substrate including a plurality of wiring layers and having a plurality of first electrodes on one surface of the first substrate, a second substrate provided to face the first substrate and having a second electrode facing the first electrodes, and a liquid crystal layer sealed between the first substrate and the second substrate, wherein a thickness in a peripheral portion in a plane of the first substrate is larger than a thickness in a central portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International PatentApplication No. PCT/JP2017/001406 filed on Jan. 17, 2017, which claimspriority benefit of Japanese Patent Application No. JP 2016-012034 filedin the Japan patent office on Jan. 26, 2016. Each of theabove-referenced applications is hereby incorporated herein by referencein its entirety.

TECHNICAL FIELD

The present disclosure relates to a liquid crystal display device using,for example, LCOS (Liquid crystal on silicon), and an electronicapparatus including such a liquid crystal display device.

BACKGROUND ART

In liquid crystal display devices using LCOS technology, a liquidcrystal is sealed between a silicon (Si) chip serving as a drivesubstrate and a counter substrate. In order to secure a uniformthickness (cell gap) in the liquid crystal display devices, variousstudies and developments have been conducted for the purpose ofenhancing planarity of a surface of the silicon chip (refer to PTL 1 andPTL 2, for example).

CITATION LIST Patent Literature

[PTL 1]

Japanese Unexamined Patent Application Publication No. H08-179377

[PTL 2]

Japanese Unexamined Patent Application Publication No. 2000-194008

SUMMARY Technical Problem

In the foregoing PTL 1, for example, a dummy pixel region similar to aneffective pixel region is provided in a peripheral region to theeffective pixel region to achieve an improvement in planarity. Moreover,in PTL 2, a metal pattern is provided in a region below a seal thatseals a liquid crystal, and layout density of the metal pattern iscontrolled, thereby achieving an improvement in planarity.

However, in the liquid crystal display devices mentioned above, thecounter substrate may be deformed in a manufacturing process to causecontact between the counter substrate and the drive substrate. Alignmentfilms for liquid crystal alignment are formed on surfaces of thesubstrates, and such contact may cause damage to the alignment films.This may lead to liquid crystal misalignment, thereby resulting indegradation in display image quality.

It is therefore desirable to provide a liquid crystal display device andan electronic apparatus that make it possible to suppress degradation indisplay image quality.

[Solution to Problem]

According to an embodiment of the present disclosure, there is provideda liquid crystal display device including: a first substrate including aplurality of wiring layers and having a plurality of first electrodes onone surface of the first substrate; a second substrate provided to facethe first substrate and having a second electrode facing the firstelectrodes; and a liquid crystal layer sealed between the firstsubstrate and the second substrate, wherein a thickness in a peripheralportion in a plane of the first substrate is larger than a thickness ina central portion.

According to an embodiment of the present disclosure, there is providedan electronic apparatus including the foregoing liquid crystal displaydevice according to the embodiment of the present disclosure.

In the liquid crystal display device and the electronic apparatusaccording to the embodiments of the present disclosure, the thickness inthe peripheral portion in the plane of the first substrate including theplurality of wiring layers is larger than the thickness in the centralportion. Herein, in a manufacturing process, for example, in some cases,the second substrate may be deformed (curved) by a pressure applied whenthe first substrate and the second substrate are superposed or by anegative pressure produced when a liquid crystal is sealed. When suchdeformation causes the second substrate to come into contact with thefirst substrate, alignment films formed on respective surface (surfaceson liquid crystal layer side) of the first substrate and the secondsubstrate are damaged to cause misalignment of the liquid crystal. Thefirst substrate has a thickness larger in the peripheral portion than inthe central portion, which makes it possible to suppress contact betweenthe first and second substrates caused by the above-describeddeformation of the second substrate. Accordingly, damage to thealignment films is suppressed, and misalignment of the liquid crystal isless prone to occur.

[Advantageous Effects of Invention]

According to the liquid crystal display device and the electronicapparatus of the embodiments of the present disclosure, the thickness inthe peripheral portion in the plane of the first substrate including theplurality of wiring layers is larger than the thickness in the centralportion, which makes it possible to suppress contact between the firstsubstrate and the second substrate even in a case in which the secondsubstrate is deformed in a manufacturing process, thereby suppressingmisalignment of the liquid crystal caused by damage to the alignmentfilms. This makes it possible to suppress degradation in display imagequality.

It is to be noted that the above description is merely examples of theembodiments of the present disclosure. Effects of the embodiments of thepresent disclosure are not limited to effects described here, and may bedifferent from the effects described here or may further include anyother effect.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are provided toprovide further explanation of the technology as claimed.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the technology, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thetechnology.

FIG. 1 is a schematic cross-sectional view of a configuration of aliquid crystal display device according to a first embodiment of thepresent disclosure.

FIG. 2A is a diagram illustrating a relationship between an effectivepixel diagonal size and a recessed amount of a drive substrate in theliquid crystal display device illustrated in FIG. 1.

FIG. 2B is a diagram for description of a diagonal size illustrated inFIG. 2A and a concave shape.

FIG. 3 is a circuit diagram illustrating a configuration of a pixelcircuit of the liquid crystal display device illustrated in FIG. 1.

FIG. 4A is a diagram illustrating a relationship between a pixelposition and wiring density in the liquid crystal display deviceillustrated in FIG. 1.

FIG. 4B is a diagram illustrating a relationship between the pixelposition and the wiring density in the liquid crystal display deviceillustrated in FIG. 1.

FIG. 5 is a schematic view of stacking order of wiring layers in thedrive substrate illustrated in FIG. 1.

FIG. 6 is a plan view of a pixel configuration in a central portion ofthe drive substrate illustrated in FIG. 1.

FIG. 7 is a plan view of a pixel configuration in a peripheral portionof the drive substrate illustrated in FIG. 1.

FIG. 8 is a cross-sectional view for description of a method ofmanufacturing the drive substrate illustrated in FIG. 1.

FIG. 9 is a cross-sectional view of a process following a process inFIG. 8.

FIG. 10A is a cross-sectional view of a process following the process inFIG. 9.

FIG. 10B is a cross-sectional view of a process following the process inFIG. 10A.

FIG. 11 is a cross-sectional view of a process following the process inFIG. 10B.

FIG. 12 is a cross-sectional view for description of a method ofmanufacturing a drive substrate according to a modification example 1.

FIG. 13 is a cross-sectional view of a process following a process inFIG. 12.

FIG. 14 is a cross-sectional view of a process following the process inFIG. 13.

FIG. 15 is a schematic cross-sectional view of a configuration of aliquid crystal display device according to a modification example 2.

FIG. 16 is a schematic cross-sectional view of a configuration of aliquid crystal display device according to a second embodiment of thepresent disclosure.

FIG. 17 is a cross-sectional view for description of a method ofmanufacturing a drive substrate illustrated in FIG. 16.

FIG. 18A is a cross-sectional view of a process following a process inFIG. 17.

FIG. 18B is a cross-sectional view of a process following the process inFIG. 18A.

FIG. 18C is a cross-sectional view of a process following the process inFIG. 18B.

FIG. 19 is a cross-sectional view of a process following the process inFIG. 18C.

FIG. 20 is a functional block diagram illustrating an entireconfiguration of a projection display unit according to an applicationexample 1.

FIG. 21A is a front view of a configuration of a digital single-lensreflex camera according to an application example 2.

FIG. 21B is a back view of a configuration of the digital single-lensreflex camera according to the application example 2.

FIG. 22 is a perspective view of a configuration of a head-mounteddisplay according to an application example 3.

DESCRIPTION OF EMBODIMENTS

Some embodiments of the present disclosure are described in detail belowwith reference to drawings. It is to be noted that description is givenin the following order.

-   1. First Embodiment (Example of liquid crystal display device    including drive substrate with thickness larger in peripheral    portion than in central portion by wiring density pattern)-   2. Modification Example 1 (Another example of method of    manufacturing drive substrate)-   3. Modification Example 2 (Example in case in which wiring density    of other wiring layer is changed)-   4. Second Embodiment (Example of another liquid crystal display    device including drive substrate with thickness larger in peripheral    region than in central region)-   5. Application Examples 1 to 3 (Examples of electronic apparatus)    Configuration

FIG. 1 illustrates a liquid crystal display device (a liquid crystaldisplay device 1) according to a first embodiment of the presentdisclosure. The liquid crystal display device 1 may be, for example, areflective display device using LCOS (Liquid crystal on silicon).

The liquid crystal display device 1 may be configured, for example, bysealing a liquid crystal layer 12 between a drive substrate 10 (a firstsubstrate) and a counter substrate 20 (a second substrate). A reflectiveelectrode layer 11 including a plurality of pixel electrodes 11 a (firstelectrodes) is formed on one surface (a surface S1 on side of the liquidcrystal layer 12) of the drive substrate 10. A counter electrode 13 a (asecond electrode) is so formed on one surface (a surface on side of theliquid crystal layer 12) of the counter substrate 20 as to face thereflective electrode layer 11. A periphery of the liquid crystal layer12 is sealed by a sealing member 14.

The liquid crystal display device 1 has an effective pixel region Aincluding a plurality of pixels. Each of the pixels may include, forexample, a liquid crystal element LC, and an FET (field effecttransistor) 110 and a retention capacitor Cp that are to be describedlater. The liquid crystal element LC includes the pixel electrode 11 a,and the liquid crystal layer 12 and the counter electrode 13 a that aredisposed directly above the pixel electrode 11 a.

The drive substrate 10 may be configured, for example, by providing aplurality of wiring layers (herein, two wiring layers 15 a and 15 b) ona substrate made of silicon (Si). In the drive substrate 10, pixelcircuits each including a thin film transistor, various wiring lines,and other components are formed over a plurality of layers. Moreover,the wiring layers configuring the pixel circuits are stacked with aninterlayer insulating film in between, and a surface of the drivesubstrate 10 is covered with an insulating film (an insulating film150). The insulating film 150 corresponds to a specific but non-limitingexample of “first insulating film” in an embodiment of the presentdisclosure.

In the drive substrate 10, a thickness t2 in a peripheral portion in aplane is larger than a thickness t1 in a central portion. Specifically,the surface S1 of the drive substrate 10 has a concave shape at least inthe effective pixel region A (the surface S1 is recessed in theeffective pixel region A). More specifically, the surface S1 of thedrive substrate 10 is curved (or is inclined from the central portiontoward the peripheral portion) in the effective pixel region A, whichcauses a thickness of the drive substrate 10 to slightly increase fromthe central portion to the peripheral portion. The reflective electrodelayer 11 is formed on the surface S1. However, the shape of the surfaceS1 of the drive substrate 10 is not limited to a slightly curved orinclined shape. It is only necessary for the surface S1 to have aconcave shape in which the thickness t2 in the peripheral portion of thedrive substrate 10 is larger than the thickness t1 in the centralportion. For example, the thickness of the drive substrate 10 may changein a stepwise fashion from the peripheral portion to the centralportion.

FIG. 2A illustrates a relationship between a size of the effective pixelregion A (an effective pixel diagonal size) and a recessed amount(arbitrary unit) of the surface S1. Herein, as the effective pixel sizeincreases, the amount of a liquid crystal injected into the liquidcrystal layer 12 in a manufacturing process increases. This causes anincrease in expansion force of the liquid crystal layer 12, and adeformation amount of the counter substrate 20 decreases with theincrease in expansion force of the liquid crystal layer 12. The recessedamount of the surface S1 may be preferably set in accordance with thedeformation amount of the counter substrate 20, i.e., the effectivepixel size. To give an example, a recessed amount (a value correspondingto a difference between the thicknesses t1 and t2) in a case in whichthe effective pixel diagonal size is a 0.6-type may be ideally 1, and arecessed amount in a case in which the effective pixel diagonal size isa 0.3-type may be ideally 0.5. Moreover, it may be desirable to form theconcave shape of the surface S1 along both a short-side direction and along-side direction at least in the effective pixel region A of thedrive substrate 10, as illustrated in FIG. 2B.

It is to be noted that a surface opposite to the surface S1 of the drivesubstrate 10 may be flat, for example. Moreover, the counter substrate20 herein is entirely curved along the shape of the surface S1 of thedrive substrate 10. This makes it possible to secure a uniform cell gapin the effective pixel region. Note that the counter substrate 20 mayhave a flat plate shape. Moreover, a recessed amount (a deformationamount) in the curved shape of the counter substrate 20 may be equal toor different from the recessed amount (a value corresponding to adifference between the thicknesses t1 and t2) of the surface S1.

The reflective electrode layer 11 is a layer including the plurality ofpixel electrodes 11 a. One of the pixel electrodes 11 a is provided toeach pixel, and the pixel electrodes 11 a may include a metal havinghigh reflectivity such as aluminum (Al). For example, an alignment film11 b may be formed on surfaces of the pixel electrodes 11 a. Thealignment film 11 b may be so formed as to cover a top surface of eachof the pixel electrodes 11 a and to fill a region between the pixelelectrodes 11 a. The alignment film 11 b may be an inorganic alignmentfilm, for example. The alignment film 11 b is subjected to alignmenttreatment in accordance with a drive mode of the liquid crystal layer12.

The liquid crystal layer 12 includes a liquid crystal that changestransmittance of light passing therethrough by application of a voltagethrough the pixel electrode 11 a and the counter electrode 13 a. Thekind (drive mode) of the liquid crystal used for the liquid crystallayer 12 is not particularly limited. Non-limiting examples of theliquid crystal may include a VA (Vertical alignment) liquid crystal anda TN (Twisted Nematic) liquid crystal.

A thickness (cell gap) of the liquid crystal layer 12 may be within arange from about 1 fÊm to about 5 fÊm both inclusive. The liquid crystallayer 12 may be interposed between the drive substrate 10 and thecounter substrate 20 without using a spacer, for example. In otherwords, in the liquid crystal display device 1, the counter substrate 20and the drive substrate 10 are superposed on each other without aspacer. The sealing member 14 formed around the liquid crystal layer 12may include an ultraviolet curable resin, for example.

The counter electrode 13 a may be formed, for example, in the entiretyof the effective pixel region A, and serves as a common electrode forthe respective pixels. The counter electrode 13 a may be configured of,for example, a transparent conductive film made of ITO (indium tinoxide). For example, an alignment film 13 b may be formed on a surfaceof the counter electrode 13 a. The alignment film 13 b may be aninorganic alignment film, for example. The alignment film 13 b issubjected to alignment treatment in accordance with the drive mode ofthe liquid crystal layer 12.

The counter substrate 20 may include, for example, a glass substrate. Inthe counter substrate 20, a color filter may be formed in addition tothe counter electrode 13 a and the alignment film 13 b mentioned above.In a case in which the liquid crystal display device 1 displays a singlecolor, a color filter of one of red (R), green (G), and blue (B) may beprovided, for example. Alternatively, in a case in which the liquidcrystal display device displays three primary colors, color filters ofR, G, and B are provided in a predetermined arrangement.

(Specific Configuration of Drive Substrate 10)

FIG. 3 illustrates a configuration of the pixel circuit of the liquidcrystal display device 1. It is to be noted that FIG. 3 illustrates aregion corresponding to four pixels P. The pixels (pixels P) eachinclude the liquid crystal element LC, the retention capacitor Cp, andthe FET 110, as illustrated in FIG. 3. A scanning line GL and a signalline DL are coupled to each of the pixels P. The scanning line GL may becoupled to, for example, a gate of the FET 110, and is a wiring lineadapted to supply a scanning signal from an unillustrated scanning linedrive circuit to the FET 110 at a predetermined timing. The signal lineDL is a wiring line adapted to supply a signal based on an image signalinputted from outside, from a signal line drive circuit to each of thepixels P. It is to be noted that the scanning line drive circuit and thesignal line drive circuit are formed in or coupled to a peripheralregion to the effective pixel region A. The pixel circuit is formed overa plurality of layers in the drive substrate 10.

In the present embodiment, one wiring layer (the wiring layer 15 a) ofthe plurality of wiring layers is provided at predetermined layoutdensity (wiring density). The wiring layer 15 a may be, for example, anuppermost wiring layer of the wiring layers formed in the drivesubstrate 10, and may be made of, for example, a metal such as aluminumand copper (Cu). In the present embodiment, a thickness of theinsulating film 150 formed on the wiring layer 15 a is larger in theperipheral portion than in the central portion. A surface of theinsulating film 150 may form, for example, the surface S1, and a concaveshape corresponding to a layout pattern of the wiring layer 15 a isformed in the surface S1. The insulating film 150 may include siliconoxide (SiO₂), for example.

FIGS. 4A and 4B each illustrate an example of a relationship between apixel position and wiring density. Layout density in the peripheralportion is designed to be higher than layout density in the centralportion, as illustrated in FIGS. 4A and 4B. As a pattern of change ofthe layout density, the layout density may slightly change asillustrated in FIG. 4A, or may change in a stepwise fashion asillustrated in FIG. 4B. However, the layout density may preferablychange slightly as illustrated in FIG. 4A. This makes it possible toreduce an influence of processing variation by an apparatus in a CMPprocess to be described later and to form a slightly curved shape,thereby improving uniformity. Moreover, a layout density difference dlbetween the central portion and the peripheral portion may be desirablyabout 5% or more.

FIGS. 5 to 7 each illustrate an example of the pixel circuit having thewiring layer 15 a as described above. FIG. 5 is a schematic view fordescription of a stacking configuration of the respective wiring layersprovided in the drive substrate 10. FIG. 6 illustrates a pixelconfiguration in the central portion of the effective pixel region A,and FIG. 7 illustrates a pixel configuration in the peripheral portion.

In the drive substrate 10, a semiconductor layer (a Si diffusion layer111) of the FET 110, a gate electrode 110G, the scanning line GL, andthe signal line DL are stacked in order from a silicon substrate, asillustrated in FIG. 5. Interlayer coupling between the respective wiringlayers is made through vias V1, V2, and V3. In this stackingconfiguration, a source electrode 110S and a drain electrode 110Dforming the FET 110 are provided in the same layer as the scanning lineGL. Moreover, the retention capacitor Cp is formed in the same layer asthe gate electrode 110G and the Si diffusion layer 111.

The wiring layer 15 a may be provided, for example, in a layer (herein,the same layer as the signal line DL) between the FET 110 and the pixelelectrode 11 a, and is electrically coupled to the pixel electrode 11 athrough the via V1. In the wiring layer 15 a, wiring density in theperipheral portion may be higher than wiring density in the centralportion as illustrated in FIGS. 6 and 7. More specifically, an intervalbetween wiring lines (wiring lines 15 a 2) provided in the peripheralportion may be smaller than an interval between wiring lines (wiringlines 15 a 1) provided in the central portion, and an area occupied bythe wiring lines in the peripheral portion may be larger than an areaoccupied by the wiring lines in the central portion. In particular,although not illustrated, an interval between the wiring lines or anarea occupied by the wiring lines in a region between the centralportion and the peripheral portion may be designed to change graduallyor in a stepwise fashion from the central portion to the peripheralportion.

It is to be noted that layouts illustrated in FIGS. 6 and 7 are merelyexamples, and layouts of respective components including the wiringlines 15 a 1 and 15 a 2 are not limited thereto. The planar shape ofeach of the wiring lines 15 a 1 and 15 a 2 is not limited to arectangular shape illustrated in FIGS. 6 and 7, and may be any othershape. Moreover, in the wiring layer 15 a, one wiring line (the wiringline 15 a 1 or 15 a 2) is provided for each of the pixels; however, aplurality of wiring lines (that may include a dummy wiring line) may beprovided in each of the pixels.

(Method of Manufacturing Drive Substrate 10)

The drive substrate 10 as described above may be formed as follows, forexample. FIGS. 8, 9, 10A, 10B, and 11 are cross-sectional views fordescription of processes of manufacturing the drive substrate 10. It isto be noted that these drawings selectively illustrate only a regioncorresponding to two pixels in the peripheral portion and a regioncorresponding to two pixels in the central portion.

First, a plurality of FETs 110 are formed in a selective region on thesubstrate 120 made of, for example, silicon with use of various kinds ofthin film processes, as illustrated in FIG. 8.

Subsequently, the wiring layer 15 a (the wiring lines 15 a 1 and 15 a 2)made of the above-described material (for example, aluminum) is formed.More specifically, an interlayer insulating film 121 is formed to coverthe FETs 110, as illustrated in FIG. 9. Thereafter, a film of aluminumis formed with use of, for example, a sputtering method, and then thewiring line 15 a 2 and the wiring line 15 a 1 are respectively formed inthe peripheral portion and the central portion with use of aphotolithography method and etching. Each of the wiring lines 15 a 1 and15 a 2 is electrically coupled to corresponding one therebelow of theFETs 110 through a via 122 (corresponding to the via V2 in FIGS. 5 to 7)formed in the interlayer insulating film 121.

Next, the insulating film 150 (insulating films 123 and 124) is formedon the wiring lines 15 a 1 and 15 a 2. First, the insulating film 123made of, for example, SiO₂ is formed with a predetermined thickness withuse of, for example, HDP (High Density Plasma) technology to cover thewiring lines 15 a 1 and 15 a 2, as illustrated in FIG. 10A. Accordingly,the insulating film 123 is formed while a difference in level caused bythe wiring lines 15 a 1 and 15 a 2 remains. Subsequently, the insulatingfilm 124 made of, for example, SiO₂ is formed by, for example, a plasmaCVD (Chemical Vapor Deposition) method, as illustrated in FIG. 10B. Thethus-formed insulating film 124 has a thickness larger in the peripheralportion having high wiring density than in the central portion havinglow wiring density.

Thereafter, part on surface side of the insulating film 124 is removedwith use of, for example, CMP (Chemical Mechanical Polishing). Thiscauses a thickness t12 in the peripheral portion of the insulating film124 to be larger than a thickness t11 in the central portion of theinsulating film 124, as illustrated in FIG. 11. Thus, the insulatingfilm 150 having a thickness different in the peripheral portion and thecentral portion is formed. In other words, the surface S1 having aconcave shape is formed in the drive substrate 10. Thus, the drivesubstrate 10 is formed.

Effects

In the liquid crystal display device 1 according to the presentembodiment, a voltage corresponding to an image signal is applied to theliquid crystal layer 12 in each of the pixels through the pixelelectrode 11 a and the counter electrode 13 a. This causes transmittanceof the liquid crystal layer 12 to change for each of the pixels. Lighthaving entered from the counter substrate 20 is reflected by thereflective electrode layer 11, and thereafter, the reflected light ismodulated in each of the pixels while passing through the liquid crystallayer 12. The thus-modulated light is displayed as an image.

Herein, in such a liquid crystal display device 1, the drive substrate10 and the counter substrate 20 are pressurized when being superposed ina manufacturing process. Moreover, when a liquid crystal is sealedbetween the drive substrate 10 and the counter substrate 20 to from theliquid crystal layer 12, a negative pressure is produced. Under suchpressures, the counter substrate 20 is deformed (curved), and in somecases, such deformation may cause the counter substrate 20 to come intocontact with the drive substrate 10. As a result, the alignment filmsformed on the surface of the drive substrate 10 and the surface of thecounter substrate 20 (the surfaces on side of the liquid crystal layer12) are damaged to cause misalignment of the liquid crystal.

On this point, in the present embodiment, the drive substrate 10 has athickness larger in the peripheral portion than in the central portion,more specifically, the surface S1 of the drive substrate 10 has aconcave shape, which makes it possible to keep the counter substrate 20from contact with the drive substrate 10 even in a case in which thecounter substrate 20 is deformed as described above. Thus, damage to thealignment films 11 b and 13 b is suppressed, and misalignment of theliquid crystal is less prone to occur.

As described above, in the present embodiment, the thickness t2 in theperipheral portion in the plane of the drive substrate 10 is larger thanthe thickness t2 in the central portion. Thus, even in a case in whichthe counter substrate 20 is deformed in a manufacturing process, it ispossible to suppress contact between the drive substrate 10 and thecounter substrate 20, thereby suppressing misalignment of the liquidcrystal caused by damage to the alignment films. This makes it possibleto suppress degradation in display image quality.

Next, description is given of modification examples of the foregoingfirst embodiment and other embodiments. In the following, substantiallysame components as those in the foregoing first embodiment are denotedwith same reference numerals, and any redundant description thereof isomitted.

MODIFICATION EXAMPLE 1

FIGS. 12 to 14 are diagrams for description of a method of manufacturinga drive substrate according to a modification example 1. In theforegoing first embodiment, in the method of manufacturing the drivesubstrate 10, the wiring layer 15 a made of aluminum is formed withpredetermined wiring density, and thereafter, an insulating film formedon the wiring layer 15 a is polished by CMP to form the concave shape.In the modification example, description is given of a technique offorming a concave shape with use of a so-called damascene process, forexample, in a case in which the wiring layer 15 a is made of, forexample, copper.

More specifically, first, grooves H1 and H2 are respectively formed inthe central portion and the peripheral portion on a top surface of theinsulating film 125 as illustrated in FIG. 12. Widths of the grooves H1and H2 are different from each other. Subsequently, a metal layer 126made of copper is formed by, for example, a sputtering method to fill inthe grooves H1 and H2, as illustrated in FIG. 13. Thereafter, part ofthe metal layer 126 is removed from surface side with use of, forexample, CMP. Thus, the wiring layer 15 a is so formed as to be embeddedin the insulating film 125, and a thickness t22 in the peripheralportion is larger than a thickness t21 in the central portion. Formingthe insulating film 150 on the insulating film 125 and the wiring layer15 a makes it possible to form the surface of the insulating film 150 ina concave shape. In other words, it is possible to form the surface S1having a concave shape in the drive substrate 10.

MODIFICATION EXAMPLE 2

FIG. 15 illustrates a configuration of a liquid crystal display deviceaccording to a modification example 2. The foregoing first embodimentinvolves an example in which the wiring layer 15 a is provided in anuppermost layer of the drive substrate 10; however, the wiring layer 15a may not be necessarily provided in the uppermost layer. For example,in the present modification example, the wiring layer 15 a is the secondwiring layer from the top of the wiring layers provided in the drivesubstrate 10.

In the present modification example, a concave shape corresponding to apattern of the wiring density of the wiring layer 15 a is formed in aninterlayer insulating film 151 formed on the wiring layer 15 a by asimilar technique to that in the foregoing first embodiment. A wiringlayer 15 c and the insulating film 150 are formed in order on a topsurface of the interlayer insulating film 151 to form a concave shape inthe surface S1 of the drive substrate 10.

It is to be noted that, in the present modification example, the secondwiring layer from the top is formed with predetermined wiring density asthe wiring layer 15 a; however, in a case in which the drive substrate10 includes three or more wiring layers, any of the third and laterwiring layers from the top may have the above-described wiring density(any of the third and later wiring layers from the top may serve as thewiring layer 15 a). Further, a plurality of wiring layers 15 a havingthe above-described wiring density may be formed.

SECOND EMBODIMENT

FIG. 16 illustrates a configuration of a liquid crystal display deviceaccording to a second embodiment of the present disclosure. The liquidcrystal display device may be, for example, a reflective display deviceusing LCOS (liquid crystal on silicon), as with the liquid crystaldisplay device 1 of the foregoing first embodiment. Moreover, the liquidcrystal layer 12 is sealed between the drive substrate 10 and thecounter substrate 20. The reflective electrode layer 11A including theplurality of pixel electrode 11 a is formed on one surface (the surfaceS1 on side of the liquid crystal layer 12) of the drive substrate 10.The counter electrode 13 a is so formed on one surface (a surface onside of the liquid crystal layer 12) of the counter substrate 20 as toface the reflective electrode layer 11. A periphery of the liquidcrystal layer 12 is sealed by the sealing member 14.

Moreover, in the drive substrate 10, a plurality of wiring layers(wiring layers 21) may be provided on a substrate made of, for example,silicon. In the wiring layers 21, a pixel circuits each including a thinfilm transistor, various wiring lines, and other components are stackedwith an interlayer insulating film in between. An insulating film 127 isformed on the wiring layers 21. In other words, the surface of the drivesubstrate 10 is covered with the insulating film 127. The insulatingfilm 127 corresponds to a specific but non-limiting example of “secondinsulating film” in an embodiment of the present disclosure.

In the drive substrate 10, as with the foregoing first embodiment, thethickness t2 in the peripheral portion in the plane is larger than thethickness t1 in the central portion. Specifically, the surface S1 of thedrive substrate 10 (a surface of the insulating film 127) has a concaveshape in the effective pixel region A. This causes the thickness of thedrive substrate 10 to slightly increase from the central portion to theperipheral portion. The reflective electrode layer 11 is formed on thesurface S1.

However, in the present embodiment, it is designed to form a flatinterlayer insulating film on the wiring layers 21 by providing, forexample, a dummy wiring line in the wiring layers 21. In other words,unlike the first embodiment, a difference in in-plane wiring density inthe wiring layer 21 is reduced to form the interlayer insulating film ina surface shape as flat as possible. Thereafter, the surface of theinsulating film 127 formed on surface side of the drive substrate 10 isprocessed to have a concave shape, which makes it possible to form thedrive substrate 10 having the surface S1 similar to that in theforegoing first embodiment.

More specifically, the drive substrate 10 is formed as follows. First, alayout of the wiring density of the wiring layer 21 and other layoutsare appropriately designed as illustrated in FIG. 17 to form aninsulating film 127 a having a flat surface (having a flat surface S110)on the wiring layer 21.

Subsequently, a photoresist film 128 having a predetermined pattern isformed on the surface S110 of the insulating film 127 a. In thephotoresist film 128, layout density of openings h3 in the centralportion is different from that in the peripheral portion. Morespecifically, the layout density of the openings h3 gradually decreasesfrom the peripheral portion to the central portion. For example, dryetching is performed with use of the photoresist film 128 having such apattern as a mask, as illustrated in FIG. 18B, to remove a selectiveregion of the surface of the insulating film 127 a. Thereafter, thephotoresist film 128 is removed to form, on the surface of theinsulating film 127 a, a concave pattern 127 p having similar layoutdensity to the layout density of the openings h3 of the photoresist film128, as illustrated in FIG. 18C.

Thereafter, the surface S110 of the insulating film 127 a in which theconcave pattern 127 p is formed is removed by, for example, CMP to formthe surface S1 having a concave shape, as illustrated in FIG. 19.

Even in the present embodiment, as with the foregoing first embodiment,the thickness t2 in the peripheral portion in the plane of the drivesubstrate 10 is larger than the thickness t1 in the central portion.This makes it possible to suppress contact between the drive substrate10 and the counter substrate 20 and suppress misalignment of the liquidcrystal caused by damage to the alignment films even in a case in whichthe counter substrate 20 is deformed in a manufacturing process. Thus,similar effects to those in the foregoing first embodiment areachievable.

Next, description is given of application examples of the liquid crystaldisplay devices according to the foregoing embodiments and modificationexamples. The liquid crystal display devices according to the foregoingembodiments and examples are applicable to various electronicapparatuses. Any of the liquid crystal display devices may be mountedin, for example, a projector (a projection display unit), a viewfinderof a camera, and a head-mounted display, as described below.

APPLICATION EXAMPLE 1

FIG. 20 is a functional block diagram illustrating an entireconfiguration of a projection display unit (a projection display unit 2)according to an application example 1. The projection display unit 2 maybe, for example, a display unit that projects an image on a screen 200(a projection surface). The projection display unit 2 may be coupled toan external image supplier through an interface (I/F), and may performprojection on the screen 200 on the basis of an image signal inputted tothe I/F. Non-limiting examples of the external image supplier mayinclude computers such as personal computers and various kinds of imageplayers.

The projection display unit 2 may include, for example, a light sourcedriver 31, a light source device 32, an optical modulator 1A, aprojection optical system 33, an image processor 34, a frame memory 35,a panel driver 36, a projection optical system driver 37, and acontroller 30.

The light source driver 31 outputs a pulse signal for control of a lightemission timing of a light source provided in the light source device32. The light source driver 31 may include, for example, a PWM setter, aPWM signal generator, a limiter, and other components that are notillustrated, and controls a light source driver of the liquid crystaldisplay device 1 on the basis of control by the controller 30 to performPWM control of the light source, thereby turning on or off the lightsource or adjusting luminance.

The light source device 32 may include, for example, a light source, alight source driver, and a current value setter. The light source driverdrives the light source, and the current value setter sets a currentvalue when driving the light source. The light source driver generates apulse current having a current value set by the current value setter insynchronization with a pulse signal inputted from the light sourcedriver 31 on the basis of power supplied from an unillustrated powersource circuit. The generated pulse current is supplied to the lightsource.

The optical modulator lA modulates light (illumination light) outputtedfrom the light source device 32 on the basis of the image signal togenerate image light. The optical modulator 1A may include one or morereflective liquid crystal devices. Any of the liquid crystal displaydevices of the foregoing embodiments and examples is applied to theoptical modulator 1A. The optical modulator 1A may include, for example,a liquid crystal panel that modulates blue light, a liquid crystal panelthat modulates red light, and a liquid crystal panel that modulate greenlight. Color light of R, color light of G, and color light of B that aremodulated by the optical modulator lA may be combined by, for example, across dichroic prism to be guided to the projection optical system 33.

The projection optical system 33 may include, for example, a lens groupthat projects the light modulated by the optical modulator 1A on thescreen 200 to form an image.

The image processor 34 acquires the image signal inputted from outside,and may perform, for example, determination of an image size,determination of resolution, and determination of a still image or amoving image. In a case with the moving image, the image processor 34may also determine, for example, an image data attribute such as a framerate. Moreover, in a case in which the resolution of the acquired imagesignal is different from display resolution of each of the liquidcrystal panels of the optical modulator 1A, the image processor 34performs resolution conversion. The image processor 34 develops theimage having been subjected to these processes in the frame memory 35for each frame, and outputs, to the panel driver 36, the image developedin the frame memory 35 for each frame as a display signal.

The panel driver 36 drives each of the liquid crystal panels of theoptical modulator 1A. The panel driver 36 drives each of the liquidcrystal panels to change transmittance of light through each of thepixels provided in each of the liquid crystal panels, thereby forming animage.

The projection optical system driver 37 includes a motor that drives alens provided in the projection optical system 33. The projectionoptical system driver 37 may drive, for example, the projection opticalsystem 33 in accordance with control by the controller 30 to performadjustment such as zoom adjustment, focus adjustment, and diaphragmadjustment.

The controller 30 controls the light source driver 31, the imageprocessor 34, the panel driver 36, and the projection optical systemdriver 37.

APPLICATION EXAMPLE 2

FIGS. 21A and 21B each illustrate an appearance of a digital single-lensreflex camera 410. The digital single-lens reflex camera 410 mayinclude, for example, a main body 411, a lens 412, a grip 413, a displaysection 414, and a viewfinder 415. Any of the liquid crystal displaydevices of the foregoing embodiments and examples is mounted in thedisplay section 14 or the viewfinder 415.

APPLICATION EXAMPLE 3

FIG. 22 illustrates an appearance of a head-mounted display 420. Thehead-mounted display 420 may include an eyeglass display section 421 anda support 422. Any of the liquid crystal display devices of theforegoing embodiments and examples is mounted in the display section421.

Although description has been made by giving the example embodiments andthe modification examples as mentioned above, the contents of thepresent disclosure are not limited to the above-mentioned exampleembodiments and modification examples and may be modified in a varietyof ways. For example, the position, shape, and number of each of thecomponents of the liquid crystal display devices described in theforegoing example embodiments and examples are merely examples, and allof the components may not be necessarily provided, and other componentsmay be further provided.

It is to be noted that the present disclosure may have the followingconfigurations.

(1) A liquid crystal display device, including:

-   -   a first substrate including a plurality of wiring layers and        having a plurality of first electrodes on one surface of the        first substrate;    -   a second substrate provided to face the first substrate and        having a second electrode facing the first electrodes; and    -   a liquid crystal layer sealed between the first substrate and        the second substrate,    -   wherein a thickness in a peripheral portion in a plane of the        first substrate is larger than a thickness in a central portion.

(2) The liquid crystal display device according to (1), wherein asurface on the liquid crystal layer side of the first substrate has aconcave shape.

(3) The liquid crystal display device according to (2), wherein

-   -   a plurality of pixels are provided, and    -   the concave shape is formed in an effective pixel region.

(4) The liquid crystal display device according to (2), wherein theconcave shape is a shape slightly curved from the peripheral portion tothe central portion.

(5) The liquid crystal display device according to any one of (1) to(4), wherein layout density of a first wiring layer of the wiring layersis higher in the peripheral portion than in the central portion.

(6) The liquid crystal display device according to (5), wherein thefirst wiring layer is an uppermost wiring layer of the wiring layers.

(7) The liquid crystal display device according to (5) or (6), wherein

-   -   a field effect transistor is provided for each of the first        electrodes in the wiring layers, and    -   the first wiring layer is provided in a layer between the field        effect transistors and the first electrodes.

(8) The liquid crystal display device according to any one of (5) to(7), wherein

-   -   the first substrate has a first insulating film on the first        wiring layer, and    -   a thickness of the first insulating film is larger in the        peripheral portion than in the central portion.

(9) The liquid crystal display device according to any one of (5) to(8), wherein layout density of the first wiring layer changes from thecentral portion to the peripheral portion in a stepwise fashion orslightly.

(10) The liquid crystal display device according to any one of (5) to(9), wherein in the first wiring layer, an interval between wiring linesin the peripheral portion is smaller than an interval between wiringlines in the central portion.

(11) The liquid crystal display device according to any one of (5) to(10), wherein in the first wiring layer, an area occupied by wiringlines in the peripheral portion is larger than an area occupied bywiring lines in the central portion.

(12) The liquid crystal display device according to any one of (1) to(11), wherein

-   -   a second insulating film is provided on the one or more wiring        layers, and    -   the second insulating film has a thickness larger in the        peripheral portion than in the central portion.

(13) The liquid crystal display device according to any one of (1) to(12), wherein

-   -   the first electrode is a reflective electrode, and    -   the second electrode is a transparent electrode.

(14) The liquid crystal display device according to any one of (1) to(13), wherein

-   -   the first substrate includes a silicon (Si) substrate, and    -   the second substrate includes a glass substrate.

(15) An electronic apparatus provided with a liquid crystal displaydevice, the liquid crystal display device including:

-   -   a first substrate including a plurality of wiring layers and        having a plurality of first electrodes on one surface of the        first substrate;    -   a second substrate provided to face the first substrate and        having a second electrode facing the first electrodes; and    -   a liquid crystal layer sealed between the first substrate and        the second substrate,    -   wherein a thickness in a peripheral portion in a plane of the        first substrate is larger than a thickness in a central portion.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

REFERENCE SIGNS LIST

-   1 liquid crystal display device-   10 drive substrate-   11 reflective electrode layer-   11 a pixel electrode-   11 b, 13 b alignment film-   12 liquid crystal layer-   13 a counter electrode-   14 sealing member-   15 a, 15 b, 15 c, 21 wiring layer-   15 a 1, 15 a 2 wiring line-   20 counter substrate-   110 FET-   150 insulating film-   1A optical modulator-   2 projection display unit-   A effective pixel region-   S1 surface-   t1, t2, t11, t12, t21, t22 thickness

The invention claimed is:
 1. A liquid crystal display device,comprising: a first substrate that includes a plurality of wiring layersand a plurality of first electrodes on a first surface of the firstsubstrate, wherein a specific wiring layer of the plurality of wiringlayers includes wiring lines, and a layout density of the wiring linesin the specific wiring layer is higher in a peripheral portion of thefirst substrate than in a central portion of the first substrate; asecond substrate that faces the first substrate, wherein the secondsubstrate includes a second electrode that faces the plurality of firstelectrodes; and a liquid crystal layer between the first substrate andthe second substrate, wherein a first thickness of the peripheralportion of the first substrate is greater than a second thickness of thecentral portion of the first substrate.
 2. The liquid crystal displaydevice according to claim 1, wherein a shape of the first surface of thefirst substrate is a concave shape.
 3. The liquid crystal display deviceaccording to claim 2, further comprises an effective pixel region thatincludes a plurality of pixels, wherein the effective pixel regionincludes the concave shape of the first surface.
 4. The liquid crystaldisplay device according to claim 3, wherein the effective pixel regionincludes the first thickness and the second thickness.
 5. The liquidcrystal display device according to claim 2, wherein the concave shapeof the first substrate extends from the peripheral portion of the firstsubstrate to the central portion of the first substrate.
 6. The liquidcrystal display device according to claim 3, wherein an amount of recessat a center of the effective pixel region is based on an effective pixeldiagonal size; the amount of recess corresponds to a difference betweenthe first thickness and the second thickness, and the effective pixeldiagonal size corresponds to a size of the effective pixel region. 7.The liquid crystal display device according to claim 1, wherein thespecific wiring layer is an uppermost wiring layer among the pluralityof wiring layers.
 8. The liquid crystal display device according toclaim 1, further comprising a plurality of field effect transistorscoupled to at least one of the plurality of first electrodes, whereinthe specific wiring layer is between the plurality of field effecttransistors and the at least one of the plurality of first electrodes.9. The liquid crystal display device according to claim 1, furthercomprising: a first insulating film on the specific wiring layer; and asecond insulating film on the first insulating film, wherein a thirdthickness of the second insulating film in the peripheral portion of thefirst substrate is greater than a fourth thickness of the secondinsulating film in the central portion of the first substrate.
 10. Theliquid crystal display device according to claim 1, wherein the layoutdensity of the wiring lines changes from the central portion of thefirst substrate to the peripheral portion of the first substrate in astepwise fashion.
 11. The liquid crystal display device according toclaim 1, wherein the layout density of the wiring lines changes from thecentral portion of the first substrate to the peripheral portion of thefirst substrate gradually.
 12. The liquid crystal display deviceaccording to claim 1, wherein an interval between the wiring lines inthe peripheral portion of the first substrate is smaller than aninterval between the wiring lines in the central portion of the firstsubstrate.
 13. The liquid crystal display device according to claim 1,wherein an area associated with the wiring lines in the peripheralportion of the first substrate is larger than an area associated withthe wiring lines in the central portion of the first substrate.
 14. Theliquid crystal display device according to claim 1, further comprisingan insulating film on the specific wiring layer of the plurality ofwiring layers, wherein a third thickness of the insulating film in theperipheral portion of the first substrate is greater than a fourththickness of the insulating film in the central portion of the firstsubstrate.
 15. The liquid crystal display device according to claim 1,wherein each of the plurality of the first electrodes is a reflectiveelectrode, and the second electrode is a transparent electrode.
 16. Theliquid crystal display device according to claim 1, wherein the firstsubstrate comprises silicon (Si), and the second substrate comprises aglass.
 17. An electronic apparatus, comprising: a liquid crystal displaydevice that includes: a first substrate that includes a plurality ofwiring layers and a plurality of first electrodes on a first surface ofthe first substrate, wherein a specific wiring layer of the plurality ofwiring layers includes wiring lines, and a layout density of the wiringlines in the specific wiring layer is higher in a peripheral portion ofthe first substrate than in a central portion of the first substrate; asecond substrate that faces the first substrate, wherein the secondsubstrate includes a second electrode that faces the plurality of firstelectrodes; and a liquid crystal layer between the first substrate andthe second substrate, wherein a first thickness in the peripheralportion of the first substrate is larger than a second thickness in thecentral portion of the first substrate.
 18. The liquid crystal displaydevice according to claim 1, further comprising: a first alignment filmon the plurality of first electrodes; and a second alignment film on thesecond electrode, wherein the second alignment film is different fromthe first alignment film.